DESCRIPTION: This research is a psychoacoustic investigation into the limitations imposed on auditory analysis by sensorineural hearing loss and the mechanisms of peripheral processing most affected by cochlear pathology. It focuses on the linearized response growth associated with cochlear pathology, which modern physiological research has shown to be a fundamental mechanism of cochlear dysfunction, and which promises to largely explain both abnormal temporal resolution and abnormal frequency resolution in persons with cochlear hearing loss. The research will employ nonsimultaneous masking to obtain valid and reliable psychoacoustic measures of response growth and will quantify the relation between response growth and amount of hearing loss, which will be of significant value for the design of hearing-aid compression schemes in individual patients. The research will also investigate cochlear transduction mechanisms and the types of cochlear damage underlying cochlear hearing loss in individual patients through the use of psychoacoustic measures of low-frequency acoustic biasing, which recent physiological research, of basilar-membrane vibration and auditory-nerve response, has shown to directly reflect basic cochlear transduction processes in outer and innerhair cells. The results of the acoustic biasing experiments may lead to better differential diagnoses of underlying cochlear pathologies in individual patients and thereby point the way to more effective treatment.